FgLEU1在禾谷镰刀菌亮氨酸生物合成及产毒致病中起关键作用

为挖掘新型药剂的潜在靶标,利用靶向基因敲除和互补技术研究赤霉病病原菌禾谷镰刀菌Fusarium graminearum中必需氨基酸亮氨酸合成酶编码基因FgLEU1的功能,并测定禾谷镰刀菌的生物学表型。结果表明,FgLEU1编码亮氨酸合成途径中的3-异丙基苹果酸脱水酶,其敲除突变体表现亮氨酸营养缺陷。生物学表型测定结果显示,与野生型菌株相比,FgLEU1敲除突变体的产孢量和孢子萌发率显著下降,产孢量仅为野生型菌株的20.96%,培养4 h后孢子萌发率下降了49.45%,且合成脱氧雪腐镰刀烯醇（呕吐毒素）能力丧失,在麦穗上的致病力下降,仅能侵染接种小穗,赤霉病症状不能扩展。外源添加一定量的亮氨酸、FgLeu1催化产物或导入含启动子的全长FgLEU1基因可以恢复敲除突变体表型缺陷。表明FgLEU1基因在禾谷镰刀菌亮氨酸合成、菌丝孢子形成及产毒致病过程中发挥着重要作用,可作为新型安全杀菌剂的潜在研发靶标,用于持续有效控制麦类赤霉病和镰刀菌毒素。     

不同谷物籽粒木聚糖酶抑制蛋白活性的分布特征研究

为准确了解谷物中木聚糖酶抑制蛋白活性的存在情况,从而进一步分析这种抑制蛋白活性对谷物加工中外加木聚糖酶可能产生的负面影响.选取小麦、大麦、黑麦、绿粒小麦、荞麦、燕麦、玉米、水稻和高粱9种常见的谷物为材料,测定了其籽粒以及籽粒不同部位木聚糖酶抑制蛋白的活性.结果表明,木聚糖酶抑制蛋白活性在小麦、黑麦、绿麦和荞麦中较高,分别为4.27,4.76,4.18,3.61 IA/mg;在大麦、燕麦中较低,分别为0.54,0.87 IA/mg;玉米、水稻和高粱中没有发现木聚糖酶抑制蛋白活性.进一步选取木聚糖酶抑制蛋白活性较高的小麦、黑麦和绿粒小麦,分别测定其种皮、胚和胚乳中的木聚糖酶抑制蛋白活性.结果显示,小麦种皮、胚和胚乳中的木聚糖酶抑制蛋白活性分另是0.06,3.67,4.47 IA/mg;黑麦种皮、胚和胚乳中的木聚糖酶抑制蛋白活性分别是1.70,5.42,5.39 IA/mg;绿粒小麦种皮、胚和胚乳中的木聚糖酶抑制蛋白活性分别是0,5.06,4.57 IA/mg.3种麦类表现出一致的结果,即木聚糖酶抑制蛋白活性在胚和胚乳中基本持平,并且远高于种皮.     

花坛的设计原则与方法

花坛作为一种园林绿化形式,占地不大,但对美化环境、活跃气氛、提高绿化效果有着突出的作用,因此其应用愈来愈受到人们的重视和青睐。从花坛的概念、花坛的作用、花坛的设计原则、盛花花坛和模纹花坛的设计要求这4个方面对花坛的设计作了较为系统的概括,为今后花坛在园林造景中的应用提供科学依据。     

黑曲霉木聚糖酶曲盘发酵及其粗酶性质研究

为研究黑曲霉菌株(Aspergillus niger)XZ-3S曲盘发酵木聚糖酶条件及所产粗酶的性质,采用曲盘(大小φ20cm×4cm)进行固态发酵条件研究,并对所产粗酶进行酶学性质测定。结果表明:在培养基干料100g、初始料水比1∶1.7、初始pH自然状态、相对干物料接种量10%、中间定时翻曲补水和28℃连续培养60h条件下,酶活力最高可达24 380IU/g干曲;粗酶最适反应pH5.0,最适温度50℃;温度低于50℃、pH3.0~8.0的条件下酶较稳定;EDTA(活性物质)、Cu2+、Co2+对酶有明显的激活作用,Pb2+、Mg2+、Fe2+、Mn2+、Ca2+、Fe3+、Al 3+对酶有不同程度的抑制作用。     

基质固相分散-高效液相色谱法测定土壤中的2,4-二氯苯酚和2-甲基-4-氯苯酚残留

建立了基质固相分散-高效液相色谱法(MSPD-HPLC)测定2,4-二氯苯酚(2,4-DCP)和2-甲基-4-氯苯酚(4-C-2-M P)在3种不同类型土壤中残留量的分析方法。土壤样品加入硅胶研匀后,加入2.0 m L蒸馏水使其失活,装入层析柱,用二氯甲烷洗脱。向洗脱液中加入0.5 m L乙二醇,减压浓缩并定容至1.0 m L,HPLC测定。结果表明:在0.01~2.5 mg/kg添加水平下,3种土壤中两种待测物的平均回收率在90%~118%之间,相对标准偏差(RSD)在0.1%~8.5%之间;检测限(LOD)在2~3μg/kg之间,定量限(LOQ)均为0.01 mg/kg。与经典的固-液萃取法(SLE)相比,MSPD法对2,4-DCP和4-C-2-MP的提取回收率较高。通过MSPD-HPLC法测定不同老化时间土壤样品中两待测物的回收率,验证了该方法的实用性。该法操作简单、溶剂用量少、分析时间短,适合用于土壤中2,4-DCP和4-C-2-MP残留量的检测。     

应用相互嫁接技术研究棉花对黄萎病的抗性

选用对棉花黄萎病表现不同抗性的棉花材料,应用相互嫁接的方法将抗病和感病棉花品种组合在一起构建嫁接系统,将其种植在连作多年的棉田,调查棉花黄萎病的发生情况。结果表明,自身嫁接苗与自根苗抗性差异不显著;相互嫁接植株抗/感(接穗/砧木,下同)和感/抗组合抗病效果明显强于感/感组合,但较抗/抗组合抗病性下降。研究认为,抗病材料无论作砧木还是接穗,均能抑制黄萎病的发生,说明抗病材料植株整体对棉花黄萎病菌具有抵抗能力。     

Brilliant blue G attenuates hippocampal injury of rats with acute carbon monoxide poisoning

AIM:To explore the role of ligand-gated ion channel purinergic P2X₇ receptor (P2X₇R) in acute carbon monoxide poisoning (ACMP)-induced brain injury, and to observe the effects of brilliant blue G (BBG) on ACMP-induced hippocampal injury of rats. METHODS:Male Sprague-Dawley rats (n=80) were divided into 4 groups including control group, ACMP group, ACMP +BBG group and BBG group. ACMP model was established by intraperitoneal injection of CO at 100 mL/kg. The degree of CO poisoning was determined by measuring the concentration of carboxyhemoglobin (HbCO) in venous blood. RT-qPCR was utilized to determine the mRNA level of P2X₇R. Wet-dry weight ratio was calculated to evaluate the edema in the hippocampus. ELISA was used to examine the concentrations of pro-inflammatory factors including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and IL-6. Morris water maze test was used to evaluate the learning and memory abilities. The morphological changes of the neurons located in hippocampal CA1 region were observed by HE staining. RESULTS:The rat survival rate in ACMP group (55%) was significantly reduced compared with control group (100%), while the mRNA expression of P2X₇R and the levels of pro-inflammatory factors including IL-1β, TNF-α and IL-6 in ACMP group were significantly increased (P<0.05). Moreover, ACMP administration increased the water content of hippocampal tissues and the escape latency of the rats, while decreased the exploration time in the target quadrant. All the effects induced by ACMP were reversed by BBG treatment. Additionally, ACMP treatment for 3 d resulted in cell disarrangement and morphologyical defect, and the nucleus was deeply dyed and condensed. However, BBG obviously alleviated the toxic effects of ACMP. CONCLUSION:P2X₇R is involved in ACMP-induced neuronal damage in hippocampus. BBG increases the survival rate, reduces the release of pro-inflammatory cytokines and the edema in the hippocampus, improves the learning and memory abilities, and attenuates neuronal damage in the CA1 region under ACMP.     

Interactions of agrochemicals applied to peanut; part 1: Effects on herbicides

Numerous agrochemicals are applied in peanut production systems. Field and laboratory experiments were conducted in North Carolina to characterize biological and physicochemical interactions when the herbicides clethodim, imazapic, imazethapyr, lactofen, sethoxydim, and 2,4-DB were applied in combination with adjuvants, fungicides, insecticides, and micronutrients. A wide range of interactions was noted when comparing across herbicides, weed species, and agrochemical combinations. There was little consistency across weed species for a herbicide or across herbicides for a weed species when comparing significant main effects and interactions. In most instances, when compared with the standard herbicide treatment and adjuvant applied alone, herbicide efficacy was not affected in the presence of other agrochemicals. Changes in solution pH and formation of precipitates varied according to the herbicide combinations used. Boron, manganese, and 2,4-DB often caused dramatic changes in solution pH.